Example:You have an 912 ULS engine with a serial number of 4,427.116. In the 912 ULS column, you’ll notice that the serial numbers which are inferior or equal to 4,427.532 have a TBO of 1200h / 10 years. You will also notice that the TBO can be increased to 1500h when the instructions contained in service document SB-912-041UL are followed. You can find these service documents on

These informations and much more can be found in our Engine Maintenance Logs.